Welcome to Sam's Laser FAQ!

This collection of documents, called "Sam's Laser FAQ", has a great deal of
practical information on a variety of laser related topics. If you are already
familiar with its scope, purpose, and general organization, you can go directly
to Sam's Laser FAQ Table of Contents.
However, if this is your first visit - or you have been away for awhile -
check out the summary and version update info below.

Sam's Laser FAQ provides a wealth of useful (not just textbook) information on
many types of lasers of interest to the experimenter and hobbyist:

Basic laser principles, laser safety, general laser information, laser
instruments and applications, laser and parts sources, laser discussion groups
and newsgroups, and many references, and links. There is even a list of
laser experiments and projects. (The descriptions are somewhat sparse at the
moment but there are also links to other related Web sites.)

Operation, internal construction (optical and electrical), adjustment,
and repair of a variety of commercial lasers of all types including Coherent,
Melles Griot, Spectra-Physics, Uniphase, and others. The detailed
information on some lasers including the Coherent 532 and Compass-M,
Lightwave 142 and 221, Melles Griot 05-GSD-309, and Uniphase uGreen,
cannot be obtained from any other publicly accessible source on-line
or in print.

Amateur laser construction (building lasers from raw materials rather than
from laser components). Extensive material on getting started in this
exciting and challenging pastime (often a great deal of time!) as well as
complete descriptions - with diagrams - of the home-built lasers from the
Scientific American "Amateur Scientist" columns (and the collection "Light
and its Uses") and other sources.

Sam's Laser FAQ was developed to provide a unique resource for experimenters
and hobbyists - as well as just plain old basement tinkerers. To the best of
my knowledge, nothing as comprehensive has ever been available anywhere else
in the explored universe (and almost certainly beyond) either on-line or in
print.

A Word About These Pages

Sam's Laser FAQ is declared to be a fluff-free zone! There will be no
unnecessary, superfluous, or useless graphics of any kind - including but
not limited to: dancing, gyrating, or other animated icons, colored textured
backgrounds that are impossible to read through, or forced downloading of
bit intense pictures that may be of no interest to you. Nor, will I ever
expect you to use a particular brand of Web browser to be able to effectively
access these pages. There are and never will be any advertisements, cookies,
or other impositions on your time and space. In the time that it may take
wading through a single monstrosity of the professional Web page designers
at other sites, you will be able to find out what you want to know, when
you want to know it! What a concept. :-) (Note, however, that your browser
needs to be configured properly to make sense of the many ASCII diagrams,
schematics, and tables. See the document: Suggested
Browser Settings for font and other related information.)

In return for this gold mine of information, please make a serious effort to
find the answers to your questions before contacting me. It may take just a
wee bit of effort and could stress a few neurons in the process, but there is
an excellent chance that what you seek is covered here. Should you be really
stuck - or just want to discuss lasers, I will respond to email in a timely
manner. However, if your questions indicate that you haven't even gotten past
the Welcome Page, AND I am in a good mood, you will get a somewhat polite
reply to read the appropriate chapter(s) of the FAQ. On the other hand, if it
is a bad day, and you are really really lucky, you will probably be ignored.
Don't get me wrong - I enjoy discussing lasers with laser enthusiasts and
novices alike, and will be happy to do so at almost any hour of the day or
night. However, if you're seeking some basic information, I would really
really appreciate it if you do at least a bit of your homework first. In
any case, if you do email me, I expect to be able to hit the reply key for
my mail program and not get bounced email. I will not attempt to unjumble
any anti-SPAM email addresses! I have posted over 20,000 articles to the
USENET newsgroups using my true email address. And, you won't pick up SPAM
via my private email anyhow. Even computer viruses avoid my address book since
it's on a unix system!) Yes, SPAM is a pain but I tolerate the small amount
I get resulting from postings so others will not be inconvenienced.

However, due to the increasing amount of SPAM via repairfaq.org email
addresses, I have decided to require all initial email contact from the
FAQs to be via the Feedback Form on the
Sci.Electronics.Repair FAQ
Email Links Page. (At some point my repairfaq.org email address will
cease to function.) Any reply from me will have a valid email address to
use for future correspondance. My apologies but I've already made so
many millions from all those get rich quick schemes that I've run out of
places to put it all. :)

Note: I NEVER send email attachments. If you receive a message supposedly from
one of my addresses with any sort of attachment, it is bogus and possibly a
virus - someone's address book includes my address and their computer is
infected. Send me the complete headers and I'll attempt to check it out just
hit the delete key.

A Somewhat Polite Gripe About Professional Web Sites

One of the most time consuming and annoying parts of maintaining the
Sci.Electronics.Repair FAQ and Sam's Laser FAQ is attempting to keep
the outside links up to date.
Why does it seem that most professional Web site
designers are programmed by their genes to rework the directory structure of
their Web sites every 26 microseconds??? Isn't this totally counterproductive
from a business point of view? Links that people have painstakingly set up
stop working with "Error 404" or "Server not Found" and no hint of where
they went or often if the company even still exists. So countless
person millenia are wasted attempting to relocate them?
How many just give up and take their business elsewhere?
Does it really make sense to annoy your customers?

Granted, personal Web sites that move from one ISP to another due to lower
costs or whatever may not have the luxury of being able to retain forwarding
links. But businesses and organizations should not have this issue.

In all fairness, there are a few - but very few compared to what's out there -
who do either provide direct forwarding links, or at least attempt to redirect
to an appropriate Web page. But the vast majority would seem to take the
attitude that the Web site is there to show off the skills of the Web site
designer, and not for the users of the information. But perhaps there is some
hope for it seems that the older a Web site is, the more likely it will be
to maintain its structure in the future.

Navigating Sam's Laser FAQ

Under ideal conditions, the entire 8+ MB text of Sam's Laser FAQ would be in a
single file and your access to it would be via a 100 GB/s link. In a few
years, such capabilities may appear primitive but for now, one can only dream
of avoiding the World Wide Wait. :) Therefore, the organization of these
pages ends up being a compromise. If you have the space, installing a local
copy of Sam's Laser FAQ on a reasonably fast computer would be best (though you
lose out on automatic updates). See: Sam's Laser FAQ
Local Installation for details.

Sam's Laser FAQ is divided into chapters and sections. Except
for the introductory material including the Table of Contents (ToC),
each chapter is a separate file and has its own Sub-Table of Contents
(Sub-ToC) Anything smaller than a chapter is called a section and has its own
header and link from the chapter's Sub-ToC. Multiple sections may be grouped
where they are related to one topic or related topics. For the most part,
there are no nested text files. With one or two possible exceptions, the
only files below the text files are those for diagrams and photos. To
minimize download time, there are no in-line graphics anywhere except the
Laser Equipment Gallery where relaxation is encouraged. :)

Links to return to the ToC are located at the beginning of every chapter
and links to return to its Sub-ToC (top of page) are located at the end
of the chapter as well as between major sections. There is also a link at
the end of every chapter to the next chapter.

Hyperlinks within the text will either be to other chapters or sections of
Sam's Laser FAQ (in which case they will generally be preceded with "chapter:"
or "section:" as appropriate) or to other pages on this Web site or elsewhere.
All local links have complete URLs including the filename so it is possible to
tell if the link is to some other page (if the filename doesn't match the one
currently being read).

All of Sam's Laser FAQ uses the very simplest HTML. This is partly because I
have to maintain it and partly to avoid fluff. :) I have thought about adding
a framed entry point which would include the ToC(s) down the left edge and
would be interested in any opinions you may have on this and other formatting
issues.

I realize that a fast search facility would be really nice. Eventually, I
may have one (I refuse to use free search engines that impose advertising.
They tend to be too slow anyhow.) In the meantime, realize that you can
always use Ctrl-F in your browser to search any single document. The two
special files: Sam's Laser FAQ Expanded ToC and
Sam's Laser FAQ Comprehensive Table of Contents
provide a means of using this technique to find desired topics with a minimum
of effort. You can also use the search engine on the
Drexel S.E.R FAQ Mirror Site.
However, if someone would offer to provide a fast non-commercial
search engine that I can just drop in with near zero effort, please contact me
me via the
Sci.Electronics.Repair FAQ
Email Links Page.

Sam's Laser FAQ Sites

Check out the Home and Mirror Site Locations page
for a list of places to find Sam's Laser FAQ (as well as the complete
Sci.Electronics.Repair (S.E.R) FAQ and Silicon Sam's Technology Resource
(SSTR). There, you will also find Links to ZIP files with the latest version
of the complete Sam's Laser FAQ and SSTR.

The mirror sites (no pun intended... OK, well maybe just a little
one-sided one) will always maintain a reasonably current version of this
document. Check the individual sites for the latest version and specific
viewing and download options and try to use the site nearest you to minimize
Web traffic!

There is also an early version (even predates the name "Sam's Laser FAQ") at
The Laser Resource
Library which is quite ancient (and ugly) at this point. I have no plans
to update it mainly because I have lost the password and become disgusted with
the annoying advertising imposed by the operators of that site at the time
I lost the password. :-) Or, go to
Sam's Laser FAQ Archive
for this and a couple other antiques.

We are always looking for contributions (of all types) in any and all laser
related areas to expand the content of these sites.

Request for Computer Resources in Support of Sam's Laser FAQ Development

Most of the text/html content for the Sci.Electronics.Repair FAQ and Sam's
Laser FAQ is developed in emacs on a unix system via telnet/ssh.
While some people may consider such an arrangement archaic, this allows for
rapid creation and editing, accessibility to the original files from anywhere
in the Universe via an Internet connection, less need to upload or download
files to my PC, and professionally managed system maintenance, upgrades, and
backup.

I currently have access to accounts at the University of Pennsylvania
(UPenn) and Drexel University which I use to create, edit, and test
the material in the Sci.Electronics.Repair FAQ and Sam's Laser FAQ.
The primary account I use for FAQ development is at UPenn and this
seems to be secure for the moment the situation can change from one
year to the next. The Drexel computer is probably
reliable as far as a long term relationship but for some reason,
USENET access is limited and posting doesn't seem to work at all.

Therefore, I am looking for access to 1 or 2 additional unix or linux
systems, preferably at academic institutions like colleges or
universities, but I will also consider other types of not-for-profit
organizations. For obvious reasons, I really do not want to do this in
association with anything commercial. My needs are modest: 1 GB of
disk space, telnet or ssh, ftp or sftp, emacs/gnus read/post,
muttmail, and publicly accessible Web space. Most of what I do is
editing and email so processing requirements are modest and shouldn't
impact other activities. However, a reliable supported environment is
critical to my sanity so your personal server farm isn't something of
much interest. :)

I do not want and will not accept monetary contributions for this effort.
But, a way to help the FAQ development would be to provide stable
computer access. If you know of, or are able to offer such a resource,
please contact me via the Sci.Electronics.Repair
FAQ Email Links Page. In return, of course, you get a local copy of
the absolutely latest and greatest versions of the FAQs (and space
permitting), all the associated ancillary material. And, of course,
priority email replies to technical questions! Thank you! :)

Version Update Information

While there may be small updates as well as more substantial additions
almost daily, when the number of revised and added bits reaches
a critical (but random) threshold, the version number will change. Beyond
a larger but also random threshold, an entry is added here to summarize
the major enhancements that may be noteworthy, and the version number
will increment by a large (also random) number. But, even if the version
number doesn't change, the date of this page and
Sam's Laser FAQ Comprehensive Table of Contents
will always reflect the latest ZIP file archive. The ZIP file archive is
updated whenever a file (like a .gif) is added to the Laser FAQ, or at
some somewhat random interval, usually less than 1 week. If you aren't
totally confused by now, send me email and explain what I just said so
I will understand it. :)

Commercial Stabilized HeNe Lasers.
Single or two-frequency HeNe lasers used for interferometry, metrology,
as a wavelength reference, etc. These are the lasers I get my jollies
from. :)

Much more on Hewlett Packard/Agilent metrology lasers has
been added including photos of an original 5500A laser head with
5505A display that is fully functional after some 40 years.
Many photos of the 5500A and 5500C laser heads have been added to the
Laser Equipment Gallery.

There are now high quaility scans of operation and service manuals for
several discontinued HP laser metrology products. These include the
5501A and 5501B laser heads as well as complete 5526A and 5528A
laser measurement systems (which include the 5500C and 5518A laser heads,
respectively).

Much more on Hewlett Packard/Agilent metrology lasers has
been added including photos of the bare laesr tube and laser tube
guts, replacing the tube with one from a barcode scanner,
and separate articles on evaluating used or rebuilt
HP and Zygo metrology lasers. There is also a schematic of the
optical receiver PCB used in the HP-5518A laser. See the chapter:
Commercial Stabilized HeNe Lasers.

Much more information and photos dealing with the Spectra-Physics 119
stabilized HeNe laser with the SP-259B exciter have been added to the chapter:
Commercial Stabilized HeNe Lasers.

There are now descriptions and photos of the Adlas DPY-315II laser system
(the forrunner of the Coherent Compass-M lasers) and the Crystalaser GCL
green DPSS lasers. Also, more on the JDSU uGreen and Nanolaser DPSS
lasers. All in the chapter: Commercial
SS Lasers.

There are now descriptions and photos of the Novalux Protera VECSEL
laser and Coherent D3 (Directly Doubled Diode) laser in the chapter:
Diode Lasers.

Substantial information on Hewlett Packard/Agilent metrology lasers
has been added including more detailed descriptions with photos,
wavelength/frequency measurements, common problems with troubleshooting
and repair techniques, and much more. See the chapter:
Commercial Stabilized HeNe Lasers.

There are now very nearly complete schematics for the Spectra-Physics
117 and 117A (and the substantially identical Melles Griot 05-STP-901),
Coherent 200, and Laboratory for Science 200 stabilized HeNe lasers
in the chapter: Commercial Stabilized
HeNe Lasers.

Some information on the Spectra-Physics 119 stabilized HeNe laser is now
included in the chapter: Commercial HeNe
Lasers.

Every external link in Sam's Laser FAQ (and the other documents of the
Sci.Electronics.Repair FAQ) has been checked. Most dead links have
either been removed or corrected. A very few have been left in place
with the hope that they were only dead temporarily.
If one of your links has disappeared,
contact me via the email link at the top of this page. Companies, large
and small, that constantly reorganize their Web sites in such a way that
links no longer work should be ashamed of themselves. :( :)

Additional information on stabilized HeNe lasers has been added including
the Spectra-Physics 117C and Laboratory For Science Models 200 and 220
ultra stable HeNe lasers. See the chapter:
Helium-Neon Lasers.

Substantial information on stabilized helium-neon lasers has been adeed
including both descriptions of the Spectra-Physics 117 and 117A, and the
nearly identical Melles Griot 05-STP-901. In addition, several home-built
stabilized HeNe lasers are described that have actually been constructed.
See the chapters: Commercial Stabilized
HeNe Lasers and Home-Built Helium-Neon
(HeNe) Laser.

There is now substantial information on the operation and implementation
of the Lightwave Electronics model 142 green DPSS laser based on a monolithic
NonPlanar Ring Oscillator (NPRO) and external monolithic resonant doubler,
as well as short sections on the Adlas 300 green DPSS laser and Uniphase
Nanolasers. These are in the chapter:
Commercial SS Lasers.

Scans of older laser related catalogs, brochures, price lists, and
other manufacturers' literature are being added to
Vintage Lasers and
Accessories Brochures Presently, this is mostly HeNe lasers but
should grow to cover other types as time progresses.

Substantial information on Melles Griot high power DPSS lasers has
been added to the chapters:
Solid State Lasers and
SS Laser Testing, Adjustment, Repair.
This includes interior photos, pinouts for the laser heads and controllers,
ways of modifying diode current and temperature setpoints, and common
problems and repair. These is also some information on the Spectra-Physics
ZLM laser head with T40 controller.

The principles of the Scanning Fabry-Perot Interferometer are discussed
in the chapter: Laser Instruments and
Applications along with ideas for building one of these normally
expensive devices for next to nothing.

There are now two sets of high quality fully regulated low voltage DC
inverter driven HeNe laser power supply designs including PCB layouts that
can be replicated and easily modified for various size lasers. See
"Sam's Modular HeNe Laser Power Supply 1" and "Sam's Modular HeNe Laser
Power Supply 2" in the chapter: Complete HeNe
Laser Power Supply Schematics.

There is much more information on vacuum systems and technology and as
a result, this material has been given a chapter of its own:
Vacuum Technology for Home-Built Gas Lasers.
Additions include specific details on many Hastings thermocouple vacuum gauges
and their testing, repair, and sensor cleaning; capacitance manometers,
powering up a turbo pump, and more.

The Laser Equipment Gallery now has
a large collection of photos on the Coherent Compass 315M and 532 green
DPSS lasers. There is also detailed information on the internal wiring
and drive requirements for the C315M laser in the chapter:
Solid State Lasers.

New information on vacuum systems for home-built lasers has been added
to the chapter: Amateur Laser Construction.
This includes more on rotary vane vacuum pumps and their maintenance,
home-built thermocouple vacuum gauges, vacuum testing without a vacuum
gauge, and sources for vacuum equipment and supplies.

A link to the Center for
Microwave and Lightwave Engineering (located in the Electrical and
Computer Engineering Department of Drexel University, Philadelphia, PA)
has been added to the Table of Contents. CMLE is where I am actually doing
some real laser work. :)

Sam's Laser FAQ now has its own Web domains:
laserfaq.com,
laserfaq.net, and
laserfaq.org.
Going to one of these will redirect you to a Web site with a recent version
of Sam's Laser FAQ. A German translation is also under development and will
be available there and at laserfaq.de
in the future.

The chapters on solid state lasers have progressed significantly and there
is now a separate one on Complete SS Laser Power
Supply Schematics with complete systems suitable for driving the pulsed
ruby and YAG laser heads common on the surplus market.

A couple of really ancient versions of Sam's Laser FAQ and a link to
another one have been collected at the
Sam's Laser FAQ Archive
just to offer an idea of how this collection evolved. If nothing else, it
beats counting sheep for insomnia. :)

Copyright notices have been added to the start and end of all text files.
I did this after finding bits and pieces of Sam's Laser FAQ at random
Web sites around the World with no mention of origin or author and dead
links to pages that might have had these attributions.

There is now a chapter on Laser Experiments
and Projects. This is mostly just a list of suggested topics and links
to a few laser project Web sites at the moment but should be filled in as
time passes.

There are several sections in the chapters on
Helium-Neon Lasers and
Home-Built Helium-Neon Laser describing
the use of HeNe laser tubes with one or two Brewster windows for the
construction of external mirror HeNe lasers using readily available
components.

Schematics have been added for several new HeNe laser power supplies as
well as a couple of argon ion laser heads (including the very common
Cyonics/Uniphase 2214).

One of the new wings of the Laser Equipment
Gallery presents the dissection of a green laser pointer based on diode
pumped solid state frequency doubled technology. Don't miss out on all the
exciting (and gory) details! :)

(Note: As of Summer, 2002, these courses have
been removed from the CORD Web site supposedly due to the expiration of their
funding. While the courses are available for purchase in
print form, It's a pity that this has happened. Print is not the same as
on-line, even if it were free. I am looking into hosting them on
one of my Web sites but suspect that in the end, such a request will be denied
due to commercial interests winning out over availability of information.)

Several more ion laser schematics have been added including a couple of
basic power supply designs that are easy to build as well as the circuit
diagram of the quite common NEC GLG-3030 laser head.

Several chapters including the one on home-built lasers (that was quite
bloated) have been split to decrease loading times.

Several new wings have been added to the
Laser Equipment Gallery including one with
photos of a Coherent 541 flowing gas CO2 laser - essentially a commercial
version of the type of system that can be built by a determined amateur.

Diagrams for all seven types of Home-Built Lasers similar to
those found in the Scientific American articles are now included in the
chapters on amateur laser construction. The drawings show the basic structure
and power supply for each laser assembly and should provide at least some of
the overall flavor of what is involved in building these devices from scratch.

The
Laser Equipment Gallery provides a variety of Photos of Lasers and
Laser Related Equipment inside and out. New wings will be added as
material arrives.

Note that this extensive set of photos is in addition to all those found in
Sam's Laser FAQ. Due to the number of bits in
these graphics files, the current FAQ distributions only include a page that
provides links to sites where they are resident.

Argon and Krypton Ion Lasers are now covered in great detail
providing the only known readily accessible detailed discussion of their
characteristics and maintenance, as well as power supply requirements and
system design considerations for these very desirable devices. There are
even complete schematics for several different Ar/Kr ion laser power supplies!

Two complete chapters provide extensive information on Amateur Laser
Construction including material from the Scientific American collection
"Light and its Uses" as well as the email, Web sites, articles, and
experiences of those who have been successful in building their own lasers
from scratch (not taking the easy way out and using commercial tubes or laser
diodes!) and getting them to work - or have given it their best shot trying!
Also included: basics of vacuum systems and glass working, where to get
strange parts, the well equipped home laser lab, and much much more.

A chapter on Carbon Dioxide Lasers is included as well.

The text formatting has also been greatly improved including a complete
Sub-Table of Contents for each chapter and intra-FAQ hot links that now work!